You’re 99.9 percent genetically identical to every human being you meet. George Clooney, Donald Trump, Serena Williams, your annoying coworker, the Pope — they’re all basically the same as you (genetically speaking).
Whether you’ve experienced culture shock in a foreign country or just sat down to dinner with your family and felt you couldn’t possibly be related to those weirdos, everyone has felt detached from other human beings at some point. At those moments, it’s good to remember the simple fact that we are all more alike than we are different.
Your genome is made up of 3 billion base pairs, the teeny-tiny chemical units that make up the genes that form the twisting, paired strands known as DNA. That means that between any two people, roughly 2.999 billion base pairs will be exactly the same. To put that another way, if you printed your genome, it would take up to 262,000 pages, and only 500 would differ from person to person.
Why is this? It’s because most of our genome does the same thing across the animal kingdom. Consider the differences between your house and the Notre Dame Cathedral. At first glance, they look very different, but they share a lot of similarities: both have foundations, doorways, windows, and a roof, to name just a few. The form these take differ, but their basic building blocks are the same. It’s similar with DNA. Most of the genetic building blocks are the same across species. The tiny differences between two organisms come down to a sliver of their genomes.
As a result, you’re 94 percent identical to your dog and 90 percent identical to your cat, genetically speaking. For cows, it’s 80 percent. You’re even strikingly similar to insects: the fruit fly, a popular subject of genomic research, shares 60 percent of your genes (including two-thirds of cancer genes!).
Humans are much more alike than they are different. In a world that seems to have more divisions every day, it’s important to remember our shared humanity. It’s right there in our genes.